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Installing a Beta gearbox into a Scorpion/Montecarlo

A few years back I installed an NOS gearbox from a Beta VX into my Scorpion WITHOUT disassembling, reaming out the shift-shaft, and reassembling, which, was the normal approach that people took. I promised to do a write up and I was just asked by a user to fill him in on what I had done. So here goes.

Edit: The VX gearbox did not come with a differential or cover. The VX ring gear was included which I mounted on the Scorpion differential. If you keep the Beta differential you'd also need to use the stub axle and flange from the Scorpion on the passenger side. Also, if you use the Beta differential cover you will need to change the speedometer drive gear. I used the Scorpion cover which did not require a change in speedo gear.

The shift shaft modification was actually quite simple. It just required a bit of patience, careful measurement, and hand work with a small grinder, file, and drill. It only took an hour or so.

Basically, you have to cut a small amount off the end of the Beta shift shaft, square the top so that the Scorpion shift lever will fit onto it, and drill a hole to allow mounting the shift lever.

The attached pictures illustrate the process.

First, make sure the gearbox is in neutral on both gearboxes, then carefully measure the top of the Scorpion shift shaft to document the configuration you are trying to achieve. Make sure to correctly document the orientation of the squared sides before you start grinding the flats on the Beta shift shaft.

These are my measurements but I'm not sure I could still interpret them without a gearbox in front of me. Hopefully, they will be helpful to someone else.

Next, you have to replace the top nut with one from a Scorpion gearbox. It's straightforward but requires a large socket with a thin wall to clear the case casting. I bought a socket from Harbor Freight and ground down the outside diameter until it fit.

Next, mark the lines of the flats on top of the cut shaft. I placed the Scorpion shift lever on top of the newly cut Beta shaft to mark the guide lines. I then protected the shaft penetration and seal with masking tape and used a small hand grinder to rough-in the flats. I finished them with a file until the shift lever would fit nicely onto the shaft. Just be careful not to take off too much material with the grinder before starting with the file.

Once you get the Scorpion shift lever to fit on correctly, you can use it as a guide to drill the required bolt hole. Once you get the bolt hole drilled, chamfer the hole on each side a bit to make the bolt insertion easier.

My memory is bad, but I seem to remember also having to use the Scorpion's passenger-side stub axle and flange. The Beta had an intermediate driveshaft that slide over the splined stub axle, but there were no threads to hold on the Scorpion's flange. Also had to drill and tap the front motor mounting points. I think the speedo gearing was different too; maybe.

My memory is bad, but I seem to remember also having to use the Scorpion's passenger-side stub axle and flange. The Beta had an intermediate driveshaft that slide over the splined stub axle, but there were no threads to hold on the Scorpion's flange. Also had to drill and tap the front motor mounting points. I think the speedo gearing was different too; maybe.

I should have added that the VX box did not come with a differential or cover. The VX ring gear was included which I mounted on the Scorpion differential. I used the Scorpion cover which did not require a change in speedo gear.

I'm at the point of reassembly. I have a question regarding the differential unit. Can I put the scorpion's Ring with two cv stub axles straight in the beta trans with out any worry? Do I have to worry about pre-load?

I'm at the point of reassembly. I have a question regarding the differential unit. Can I put the scorpion's Ring with two cv stub axles straight in the beta trans with out any worry? Do I have to worry about pre-load?

Also can I use the Scorpion's diff case cover in the beta trans?

Thanks,
Ralph

That's pretty much exactly what I did. But you have to use a ring gear that matches the drive gear in the gearbox so I bolted the VX ring gear to the Scorpion differential and used the Scorpion cover.

I looked at the instructions for adjusting pre-load and determined it was voodoo magic so I just went with it all the way it was.